Recently, in disk drives such as hard disks, density of data stored in magnetic media tends to increase. In accordance with this, track pitch of the magnetic media tends to be narrow. When data is read from a magnetic medium having a narrow track pitch using a magnetic read/write head, in a case where off-track occurs in the track width direction, there is a possibility that data written on a corresponding track cannot be accurately read.
In addition, in a case where off-track occurs in the track width direction at the time of writing data onto a magnetic medium having a narrow track pitch using a magnetic read/write head, thereafter, when data is read using a magnetic read/write head, there is a possibility that the data written on the track cannot be accurately read.